This is no longer urgent (but you won't like our workaround!)
Reported here for your information and in order to benefit the Mint project....
When booting Mint 4 in 'Live' mode we get working WiFi on the Atheros 5006 chipset installed in
an Acer 4315 http://global.acer.com/products/notebook/as4315.htm. **
We did this using the NDISwrapper GUI and the net5211 drivers supplied with Mint - took less than a minute - So far so great!
Then a hard disk installation was fired up from the Mint Live desktop. All went well but for the Wifi, which would no longer respond successfully to the same approach. No Wifi. Seems as though we may be unable to entirely remove the default (auto-configured) WiFi drivers from the HD installation. Just guessing. But the NDISwrapper approach just does not work on the installed version.
We tried a ton of stuff - reinstalling a couple of times via different routes, but no luck. Then we found this website that may be of interest: http://www.hbclinux.net.nz/acer4315-804.html
Simon Bridge has put together a lot of good info on the 4315 there, which in our case comes with a flaky Acer installation of Ubuntu Gutsy - hope that the information is relevant to Mint.
So, err.... we've installed Ubuntu Hardy and everything works - WiFi using NDISwrapper again - the net5211 drivers that came with the Acer-installed Ubuntu. Look forward to trying out Elyssa - and thanks to the devs for all their excellent work.
All the best, Ben